Britain's probe into last week's London bombings took on a new twist Friday with the arrest of an Egyptian chemistry expert in Cairo and a "Pakistan connection" to the attacks.
Investigators seized explosives during a raid in Leeds
The 33-year-old US-trained biochemist known as Magdy el-Nashar, a researcher at Leeds University in northern London, was being questioned for his role in last week's London bombings that killed over 50 people and injured 700.
Egyptian sources told AFP that el-Nashar, "is being interrogated to see whether he is indeed the one everybody is talking about as being involved in the London bombings."
They said el-Nashar was arrested in Cairo's southern suburb of Maadi, in the popular neighborhood of Bassatin.
Debris lies on the street following the bus bomb near Tavistock Square in London
El-Nashar is believed to have left London for a 45-day holiday in Egypt before the bombings and had intended to return there, Egypt's Interior Ministry said in a statement. He has denied any knowledge of the attacks, in which four bombers blew themselves up in three underground trains and a double-decker bus.
British police said Friday they were "aware" of an arrest in Egypt in connection with the investigation into last week's London bombings.
"We are aware of an arrest made in Cairo but are not prepared to discuss if we may or may not wish to interview (the person) in connection with this investigation," a spokeswoman for London's Metropolitan Police told AFP. "This remains a fast-moving investigation with a number of lines of enquiry, some of which may have an international dimension."
British agents are believed to be with Egyptian authorities questioning el-Nashar in Cairo.
El-Nashar the alleged bombmaker?
The US network ABC News reported the arrest earlier Friday, saying el-Nashar was the alleged bomb-maker behind the London attacks.
Citing sources including the US Federal Bureau of Investigation, ABC said the detained man was suspected of having helped set up the attackers' bomb factory.
Police officers stand outside the Iqra Learning Centre, a Muslim bookshop in Beeston, Leeds, England
The BBC said on its Web site that British police searching homes in Leeds and Buckinghamshire had found ingredients available from high-street chemists in one of the homes. They were the same kind of explosive Richard Reid had in his shoes when he tried to blow up a trans-Atlantic flight in 2001.
An acquaintance of el-Nashar told Reuters he was shocked he might be involved in the bombings.
"He had a great personality. You would never expect this kind of action from him. Impossible," said Kadhem al-Rawi, a doctor in Islamic principles from an institute in Wales.
"A Pakistan connection"
Sir Ian Blair, commissioner of London's Metropolitan Police, also confirmed on BBC radio Friday that there was "a Pakistan connection" to the bombings.
British police are reported to have given Pakistan a list of terror suspects with possible links to the London attacks. Pakistani security agencies are investigating possible links between militant groups based in Pakistan and Shehzad Tanweer, who blew himself up in a train near Aldgate underground station in London.
Tanweer had links to local militant groups, understood to be Jaish-e-Mohammed and Lashkar-e-Taiba, both involved in fighting Indian forces in Kashmir. The two groups are known to have ties with Osama bin Laden's al Qaeda network.
Jaish is loosely linked with the Jamia Manzoorul Islamia school in the eastern city of Lahore, which denied British press reports that Tanweer had studied there. Lashkar-e-Taiba also denied that Tanweer visited a campus formerly linked to the group in Muridke, near Lahore.
Pakistan's education minister, Javed Ashraf, told BBC television that "to the best of our knowledge" there was no military training at the country's network of some 10,000 madrassas, where up to 1.5 million students are educated. "If the British government tells us which madrassas we will certainly look to take action," he said.
Separately, Pakistani investigators said Friday they were questioning a British man arrested on suspicion of ties to terror groups, but that he has no known links to the London attacks.
Zeeshan Siddique, 25, was arrested on May 18 near the northwestern city of Peshawar after sneaking into Pakistan on fake documents, and is being held at the city's central jail, the officials told AFP.
"Communities will defeat terrorism"
Britain has been rattled by the fact that the masterminds of last week's carnage were apparently carried out by four Islamic extremist suicide bombers born and bred in Britain. Three of the four suspected bombers were Muslim Britons of Pakistani origin, while the fourth has been named by newspapers as a Jamaican immigrant who converted to Islam.
A Muslim man takes a moment to reflect on last Thursday's bomb attacks at a flower tribute near Edgware Road Tube Station, London
With the spotlight now on the country's Muslim community, London police chief Sir Ian Blair said Friday that Britain's Muslim communities must begin an "active engagement in counter-terrorism" following last week's London suicide bombings.
"One of the big messages that I am going to be giving is that we must seize this moment," Blair, said during a speech at a mosque in east London.
"This weekend, next week, we have to seize a moment in which the Muslim communities of Britain, helped by everybody of good will, changes from a current position of shock and disbelief into active engagement in counter-terrorism. That's the challenge," he said.
The bombings were "a perversion of the virtues of Islam", said the police chief, who was spending Friday visiting mosques and other religious buildings around London. "But, it is done... by these people who perverted in the name of Islam. And that puts a responsibility on all of us," he said.
"For you... this is the worst nightmare that can happen to the British Muslim community," Blair noted, adding that he had one "simple message" for all the British public.
Sir Ian Blair visits the Sikh community at Gurdwara Dasmesh Darbar, in east London
"It is not the police, it is not the intelligence services who will defeat terrorism. It is communities who will defeat terrorism."